I think anyone who thinks DJB's proposal was a realistic easy option needs to look at the history of the class E address space (240.0.0.0/4), and the proposals to allocate it for normal use.
Despite not changing the address length at all, the idea of doing this was abandoned because of the widespread compatibility problems across different OSes.
Sure, you could hand-wave another layer of NAT to "fix" it, just like the extended address proposals.
Hell, even using MAC addresses which begin with a number devices haven't seen before is enough to cause issues, despite following the existing standards:
https://news.ycombinator.com/item?id=13090945
And all the existing NAT / firewall / middleware devices - they're supposed to handle the extensions transparently? Having seen the many ways that ASA protocol / application fixup can mangle packets - I find it very hard to believe.
Despite not changing the address length at all, the idea of doing this was abandoned because of the widespread compatibility problems across different OSes.
Sure, you could hand-wave another layer of NAT to "fix" it, just like the extended address proposals.
Hell, even using MAC addresses which begin with a number devices haven't seen before is enough to cause issues, despite following the existing standards: https://news.ycombinator.com/item?id=13090945
And all the existing NAT / firewall / middleware devices - they're supposed to handle the extensions transparently? Having seen the many ways that ASA protocol / application fixup can mangle packets - I find it very hard to believe.